EP3338815A1 - Bone graft substitute - Google Patents

Bone graft substitute Download PDF

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Publication number
EP3338815A1
EP3338815A1 EP16206784.7A EP16206784A EP3338815A1 EP 3338815 A1 EP3338815 A1 EP 3338815A1 EP 16206784 A EP16206784 A EP 16206784A EP 3338815 A1 EP3338815 A1 EP 3338815A1
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EP
European Patent Office
Prior art keywords
granules
implant
porogen
biocompatible
composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP16206784.7A
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German (de)
English (en)
French (fr)
Inventor
Lukas Pfister
Kurt Ruffieux
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sunstar Suisse SA
Original Assignee
Sunstar Suisse SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sunstar Suisse SA filed Critical Sunstar Suisse SA
Priority to EP16206784.7A priority Critical patent/EP3338815A1/en
Priority to US16/471,107 priority patent/US20190321514A1/en
Priority to PCT/EP2017/083829 priority patent/WO2018115128A1/en
Priority to EP17822278.2A priority patent/EP3558404B1/en
Priority to EP22203780.6A priority patent/EP4144386B1/en
Priority to CN201780079095.2A priority patent/CN110087699B/zh
Priority to JP2019534244A priority patent/JP7197483B2/ja
Priority to ES17822278T priority patent/ES2954288T3/es
Publication of EP3338815A1 publication Critical patent/EP3338815A1/en
Priority to US17/234,365 priority patent/US20210236689A1/en
Priority to US17/332,833 priority patent/US20210283301A1/en
Priority to US17/472,897 priority patent/US20210402056A1/en
Priority to JP2022062671A priority patent/JP7483782B2/ja
Withdrawn legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/02—Inorganic materials
    • A61L27/12—Phosphorus-containing materials, e.g. apatite
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P1/00—Drugs for disorders of the alimentary tract or the digestive system
    • A61P1/02—Stomatological preparations, e.g. drugs for caries, aphtae, periodontitis
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K9/00—Medicinal preparations characterised by special physical form
    • A61K9/0012—Galenical forms characterised by the site of application
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K9/00—Medicinal preparations characterised by special physical form
    • A61K9/0087—Galenical forms not covered by A61K9/02 - A61K9/7023
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K9/00—Medicinal preparations characterised by special physical form
    • A61K9/14—Particulate form, e.g. powders, Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles
    • A61K9/141—Intimate drug-carrier mixtures characterised by the carrier, e.g. ordered mixtures, adsorbates, solid solutions, eutectica, co-dried, co-solubilised, co-kneaded, co-milled, co-ground products, co-precipitates, co-evaporates, co-extrudates, co-melts; Drug nanoparticles with adsorbed surface modifiers
    • A61K9/143—Intimate drug-carrier mixtures characterised by the carrier, e.g. ordered mixtures, adsorbates, solid solutions, eutectica, co-dried, co-solubilised, co-kneaded, co-milled, co-ground products, co-precipitates, co-evaporates, co-extrudates, co-melts; Drug nanoparticles with adsorbed surface modifiers with inorganic compounds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/28—Materials for coating prostheses
    • A61L27/34—Macromolecular materials
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/40—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
    • A61L27/44—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material having a macromolecular matrix
    • A61L27/46—Composite materials, i.e. containing one material dispersed in a matrix of the same or different material having a macromolecular matrix with phosphorus-containing inorganic fillers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L27/502—Plasticizers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L27/56—Porous materials, e.g. foams or sponges
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P19/00—Drugs for skeletal disorders
    • A61P19/08—Drugs for skeletal disorders for bone diseases, e.g. rachitism, Paget's disease
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
    • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
    • A61C8/0012—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools characterised by the material or composition, e.g. ceramics, surface layer, metal alloy
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2430/00—Materials or treatment for tissue regeneration
    • A61L2430/02—Materials or treatment for tissue regeneration for reconstruction of bones; weight-bearing implants

Definitions

  • the present invention relates to a porous implant mass composition for treating defects in living organisms, such as bone defects and tooth extraction wounds and also relates to the manufacture thereof. More specifically, it relates to a new optimized geometry and pore structure allowing for a mechanically stable, but highly porous bone graft substitute.
  • Bone replacement materials are important in many fields such as, for instance, orthopaedics, dental surgery, traumatology and orthodontics. Such bone replacement materials are used, for example, to fill a hole left after removal of a bone tumour, to fill a bone defect after a fracture, to fill a void remaining after tooth extraction, to augment bone prior to dental or orthopaedic implant placement or to act as a carrier for antibiotics or osteogenic substances.
  • Bone replacement materials can be classified based on their origin, namely autograft materials, where the living organism's own bone is used, and bone graft substitutes, where the material comes from another source.
  • Specific bone graft substitutes include allograft (human origin) materials, xenograft (animal origin) materials and synthetic materials.
  • autograft materials are osteoconductive as well as osteoinductive and have excellent healing potential, the amount that can be harvested is limited and donor site morbidity and associated pain are frequent for the patient.
  • bone graft substitutes are commonly used. Allograft and xenograft bone are osteoconductive and have a similar bone structure to the natural bone. However, there is a risk of disease transmission. Synthetic bone grafts can avoid the risk of disease transmission and are available in unlimited quantities. They also provide greater freedom to design and optimize the bone graft substitute for a good osteoconductivity.
  • the graft material is in close contact with the bony walls. To achieve this, it is advantageous if the bone graft material can be formed into the required shape directly during surgery. For this reason, bone graft substitutes are most commonly provided as loose granules that can adapt to the contour of any defect.
  • Allografts and xenografts typically consist of trabecular bone chips, and many synthetic bone graft substitutes seek to mimic the natural trabecular structure of the bone chips because the trabecular structures provide a lot of space between the bone chips for bone ingrowth. Unfortunately, these trabecular structures are very fragile and forming them into the required shape with sufficient pressure without breaking them is a major challenge.
  • the walls can be compacted or the porosity within the granules can be reduced.
  • both measures lead to reduced or no in-growth of the bone tissue.
  • the use of spherical granules having a homogeneous internal porosity is found to increase resistance to breakage when placed into the defect.
  • spherical granules do not provide much natural intergranular space that is desired for optimal bone ingrowth. If round spheres of identical size are densely arranged in a lattice packing, a porosity of only 26% can be calculated. By mixing small and large granules, this may even be reduced.
  • the implant according to the present invention overcomes the mentioned problems by providing an osteoconductive biocompatible bone graft substitute.
  • the bone graft substitute combines substantially the high mechanical stability of spherical porous granules without the limitation of reduced intergranular space.
  • the structure inside the granules has a high porosity whilst maintaining high stability, so that the granules can be pushed into a defect without risking significant breakage of the granules and, at the same time, the bone cells can grow into the space between the granules.
  • the surface of the granules comprises indentations, when viewed from the exterior of the granules.
  • An indentation increases the porosity within the implanted mass significantly and thus provides more space between the granules for tissue ingrowth. Due to the indentations on the granules, the granules have an irregular shape and thus an increase in the intergranular space is achieved, while mechanical stability is maintained.
  • the granules are linked together. They are coated with a very thin layer of a biocompatible and resorbable thermoplastic polymer.
  • the linking may be achieved by using a plasticizer such as a solvent or pressurized CO2 that lowers the glass transition temperature (Tg) of the coating. Subsequent condensing of the granular mass will result in pressing the coatings into each other or the coating of one granule into the mass of a second granule. Once the granules are pushed into a defect, the mass may be adapted to the geometry of the defect and thus adapted to the bony walls. Once the plasticizer is removed from the mass and the Tg rises again, a hardening of said mass occurs and thus a rigid implant forms.
  • Tg glass transition temperature
  • the granules are linked together at a few contact points only to allow for a maximum of interconnected porosity within the mass.
  • Such an implant composition according to the invention forms an open porous scaffold or composite matrix that allows in-growth and regeneration of bone tissue.
  • the moldable implant composition of the present invention includes a plurality of biocompatible granules mixed with a biocompatible polymer and a plasticizer for the polymer.
  • the plasticizer is included in an amount sufficient to condition at least a portion of the biocompatible polymer such that the implant mass can be molded (i.e., is plastically deformable).
  • the implant mass can be inserted in a bone defect where the implant mass can be deformed so as to assume the shape of the defect.
  • the moldable implant composition can be deformed, molded, and/or sculpted to have any particular shape, either in-situ or ex-situ.
  • the plasticizer is selected to cooperate with a hardening agent. Once the hardening agent is applied to the moldable implant composition, the effect of the plasticizer is neutralized and the implant composition hardens, thereby providing proper structural support.
  • the plasticizer is partially soluble in an aqueous solution such as a body fluid such that the body fluid can act as a hardening agent by extracting at least a portion of the plasticizer from the implant composition.
  • the implant composition is flowable and can take the shape of an implant site or a mold.
  • This version of the invention can be advantageous where the desired shape of the implant is convoluted and/or difficult for a practitioner to form.
  • the implant mass can more easily take the shape of the implant site or the mold.
  • the plurality of granules are formed from synthetic biomaterial such as ⁇ -tricalcium phosphate, hydroxyapatite, mixtures thereof or other synthetically generated phases of calcium phosphate.
  • granules according to Fig. 1 were modified by adding indentations from outside.
  • the porogen used was cellulose spheres.
  • the size of the porogen was selected to be within the range 355 - 500 ⁇ m.
  • the pressure applied was either 10 MPa as shown in Figure 3a , or 26 MPa as shown in Figure 3b .
  • the intergranular space was measured by image analysis of 3-D reconstructed micro-CT slices through a defined cylindrical volume filled with granules.
  • the porosity inside the granules was not measured, only the pores between the granules were analysed.
  • a) micro-CT slice through the implant mass b) removing the porosity within the granules by adjusting the contrast of the image, c) generating a 3-D model. Intergranular porosity is calculated volumetric using the 3-D model.
  • results show the significant higher mechanical force of failure of granules made according to the present invention as compared to highly porous competitor products (Bio-Oss® (Geistlich, Switzerland), Cerasorb®M (Curasan AG, Germany), BoneCeramicTM (Straumann, Switzerland)) with no reduction as compared to the spherical granules without indentations.
  • Embodiments of the present invention include moldable implant compositions for repairing a bone defect or wound.
  • the moldable implant compositions are formed from a plurality of particle-like granules.
  • a biocompatible polymer is disposed about or coated on the granules.
  • the granules and polymer are packed or agglomerated to form an implant mass and the polymer is softened with a plasticizer to make the implant mass moldable or flowable.
  • the implant mass is shaped or sculpted to form a bone implant that will fill a particular bone defect or structural void.
  • the implant composition is then allowed or caused to harden.
  • the order and timing of (i) softening the polymer, (ii) forming the implant mass, and (iii) shaping the implant mass can vary according to different embodiments of the present invention.
  • implant compositions could only be made by using spherical granules, as a certain mechanical strength of the granules is needed to allow for (i) non-destructive coating and (ii) non-destructive insertion and condensation within the defect.
  • this was limiting the porosity between the granules, reducing the amount of open space which is accessible by the tissue after implant mass insertion.
  • the inventors have found how intergranular porosity can be increased by adding surface concavities without reducing mechanical properties significantly.
  • the present invention includes biocompatible granules, which are a hard substance that provides structural support or physiological advantages to the implant mass.
  • the granules can be made of synthetic, naturally occurring, polymeric, or non-polymeric materials.
  • the granules are also degradable such that the implant degrades over time and/or be replaced with native bone tissue.
  • the biocompatible granules of the present invention can be made of naturally occurring materials such as xenografts or allografts or other animal or human derived hard substances. To those knowledgable in the art, it is clear that such materials can be ground to small particles and then granules may be made using known granulation and sintering techniques.
  • Calcium phosphate ceramics are biocompatible and can be used in various biomedical applications. Hydroxyapatite and ⁇ -TCP bioceramics and biphasic ceramics made thereof are particularly useful materials because they have similar ionic properties as the mineral components of bone. In addition, their resorption kinetics can be controlled to meet the needs of a specific therapy. Furthermore, because ⁇ -TCP is degradable, it is absorbed in vivo and can be replaced with newly formed bone.
  • biocompatible granules are selected, which have a Ferret-diameter of about 100 ⁇ m to about 4000 ⁇ m, and preferably from about 500 ⁇ m to about 1000 ⁇ m.
  • Ferret-diameter indicates that the granules may be of irregular shape
  • spherical granules allow a better handling and an easier estimation of the quantity required to fill a known volume of a cavity.
  • Spherical or other regularly-shaped and/or sized granules form a more uniform pore structure or scaffold between the adjacent particles.
  • draw-back of the well ordered structure is a low intergranular porosity. Thus it can be of advantage if the granules have an irregular shape.
  • the resultant mass was extruded through a multi-hole 800 ⁇ m-nozzle and spheronized for 3 min in a pellet-rounder to obtain granules having an average diameter of about 350 ⁇ m to about 1000 ⁇ m.
  • the obtained granular green bodies were thereafter sintered at 1100 °C for 8 hours.
  • granules having a regular or irregular surface and shape and comprise indentations are concavities or dimples.
  • Indentations in the surface of the granule may be obtained by pressing a porogen into the surface of a granule whilst it is unhardened (in the example stated above this would mean before the sintering process).
  • the porogen is spherical so as to provide concave indentations.
  • Concave surface features preferably cover at least 25% of the surface of the granule. More preferably, concave surface features preferably cover at least 50% of the surface of the granule (see Figures 2 to 4 ).
  • a method of manufacturing a porous implant composition for use in repairing a defect in a living organism comprising a plurality of biocompatible granules wherein at least a portion of the granules having surface indentations, comprises
  • the so obtained mixture was filled into a cylindrical container and pressed in a hydraulic press at 16 - 24 MPa for 2 min.
  • the cellulose spheres were thus pushed into the surface of the green body granules.
  • the granules with indentations were then dried in a drying cabinet at 70 °C overnight.
  • the obtained granular green bodies were thereafter sintered at 1100 - 1200 °C for 4 - 8 hours. After sintering, the granules were fractionated to obtain granules having an average diameter of from about 500 - 1000 ⁇ m.
  • the porogen which may be used in the present invention can be any natural or synthetic substance which is removable from the implant composition by means of burning, melting, dissolving, leaching or mechanically removal. Residues of the porogen in the final product must be low enough to allow for biocompatibility of the implant composition.
  • porogens include: polysaccharides and derivates therof, such as cellulose, microcrystalline cellulose, hydroxypropylcellulose, methylcellulose, hydroxypropyl methylcellulose, hydroxypropylmethylcellulose acetate succinate (AQOAT), ethylcellulose, carboxymethylethylcellulose, cellulose acetate phthalate, hydroxypropylmethylcellulose phthalate, croscarmellose; starch, processed starch; sodium starch glycolate, pregelatinized starch.
  • polysaccharides and derivates therof such as cellulose, microcrystalline cellulose, hydroxypropylcellulose, methylcellulose, hydroxypropyl methylcellulose, hydroxypropylmethylcellulose acetate succinate (AQOAT), ethylcellulose, carboxymethylethylcellulose, cellulose acetate phthalate, hydroxypropylmethylcellulose phthalate, croscarmellose
  • starch processed starch
  • sodium starch glycolate pregelatinized starch.
  • Examples may also be synthetic polymers and copolymers made thereof, such as polymethylmethacrylate, polyethylene , polypropylene, polystyrene, polyvinylchloride, polyvinylpyrrolidone, polyvinyl alcohol, silicones, polylactides and polyglycolides. Further examples may also be salts, such as sodium chloride, potassium chloride, sodium bicarbonate. Further examples may also be ice or frozen substances.
  • the porogen can be used by itself or if desired, in a combination with two or more types of excipients.
  • salt may be removed by leaching
  • polymer and polysaccharides may be removed by burning
  • frozen substances may be removed by melting
  • polymers may be removed by dissolving.
  • Granules having a spherical shape with the internal porosity concentrated in the core of the granule showed an average force of failure at 1.5 N.
  • the method described in this invention achieved an increase in the intergranular porosity from 40 % to 51 % while not reducing the force at failure.
  • the implant composition of the present invention may also include a biocompatible polymer disposed about the granules to form an implant mass.
  • a portion of or all of the granules are coated with the biocompatible polymer.
  • the biocompatible polymer is also degradable so as to promote absorption into the body as the implant is replaced by newly-formed living tissue.
  • Biocompatible and preferably resorbable polymers suitable for use in the present invention include poly([alpha]-hydroxyesters), poly(orthoesters), poly(ether esters), polyanhydrides, poly(phosphazenes), poly(propylene fumarates), poly(ester amides), poly(ethylene fumarates), poly(amino acids), polysaccharides, polypeptides, poly(hydroxy butyrates), poly(hydroxy valerates), polyurethanes, poly(malic acid), polylactides, polyglycolides, polycaprolactones, poly(glycolide-co-trimethylene carbonates), polydioxanones, or copolymers, terpolymers thereof or blends of those polymers.
  • the synthetic biocompatible granules may be spray-coated, preferably in a fluidized bed machine, or immersion-coated with the desired biocompatible polymer(s). Both methods lead to the biocompatible granules having advantageous properties.
  • the spray coating process in a fluidized bed machine allows the fabrication of a great number of nearly identical polymer-coated biocompatible granules in a very fast and economic manner.
  • Using the fluidized bed process allows control of the thickness of the coating layer(s) and the fabrication of biocompatible granules having multiple coating layers, which are distinct from each other.
  • the coating in fluidized bed machine results in a homogenous and continuous coating. During the coating process the granules do not adhere to each other, thus avoiding the formation of undesirable aggregates which might lead to highly inhomogeneous size distributions and coating thickness.
  • additives such as plasticizers or biologically active substances into the coating(s) can be easily controlled by the fluidized bed machine.
  • each granule is loaded with the same amount of the biologically active substances.
  • the thickness of the coating is also easily controlled. Therefore, even the release of an integrated biologically active substance is predictable and well controlled.
  • the coating of the biocompatible granules may include one or more layers of varying average thickness.
  • This embodiment of the invention allows providing biocompatible granules with several coatings for specific purposes.
  • the outermost degradable coating may be selected in accordance with a certain desired delay in degradability. This, for example, allows a retarded delivery of a bioactive substance.
  • the synthetic biocompatible granules may be coated with different coatings, each of which is degradable and displays a specific effect.
  • the biocompatible polymer coating preferably has a thickness of about 1 ⁇ m to about 300 ⁇ m, preferably of about 5 ⁇ m to about 30 ⁇ m.
  • the coating thickness of the granules can also be expressed as a weight fraction of about 4 % to about 20 % coating materials of the total weight of the implant mass, which may be loaded with additives such as plasticizers or biologically active substances.
  • additives such as plasticizers or biologically active substances.
  • the mechanical stability of an implant made of coated granules can depend on the thickness and the homogeneity of the coating. An insufficient coating thickness can cause the granules to fail to stick together. On the other hand, too much coating can cause a decrease in the pH in the vicinity of the implant during its degradation. Whether the thickness of the coating has an adverse effect on the performance of the implant depends on the particular use of the implant.
  • the biocompatible polymer and the plasticizer are selected to work in a polymer-solvent system.
  • the biocompatible polymer is selected to have a desired flexibility and tackiness when partially dissolved or softened in a particular plasticizer.
  • the plasticizer is removed (e.g., by evaporation or diffusion into the body), the biocompatible polymer hardens to form a rigid bone implant.
  • the polymer and plasticizer are chosen to give the implant a particular stiffness when softened and hardened.
  • the plasticizer can be a liquid or a gas such as pressurized CO2.
  • the plasticizer is preferably biocompatible or exhibits a very low toxicity such that it can safely exist in the bone implant once the implant has been placed in a patient.
  • Suitable plasticizers include, but are not limited to, n-methyl-2-pyrrolidone (NMP), acetone, ethyl lactate, ethyl acetate, ethyl formiate, acetyltributylcitrate, triethyl citrate, tetrahydrofuran, toluene, alcohol and carbon dioxide.
  • NMP n-methyl-2-pyrrolidone
  • acetone ethyl lactate
  • ethyl acetate ethyl formiate
  • acetyltributylcitrate triethyl citrate
  • tetrahydrofuran toluene
  • alcohol and carbon dioxide etrahydrofuran
  • the plasticizer of the present invention can be one of many other solvents or a combination
  • the plasticizer is a solvent that has solubility in aqueous medium, ranging from miscible to dispersible.
  • the plasticizer is capable of diffusing into an aqueous medium or into body fluids such as, for example, tissue fluids, such as blood serum, lymph, cerebral spinal fluid, and saliva.
  • tissue fluids such as blood serum, lymph, cerebral spinal fluid, and saliva.
  • the bone implant can also be hardened ex-situ by drawing the plasticizer out of the polymer.
  • the plasticizer is selected to be partially soluble in water. Once the implant is shaped ex-situ, such as in a mold, water is placed on the implant, thereby extracting the plasticizer and hardening the bone implant.
  • the plasticizer can be removed by evaporation (e.g., by heating and/or applying a vacuum).
  • the polymer-solvent system is designed to reduce the Tg of the biocompatible polymer to a temperature below room temperature.
  • acetone, NMP, or an alcohol is added to poly-lactic-co-glycolic acid (PLGA) until the Tg of the PLGA drops from about 45-55 °C to below room temperature.
  • PLGA poly-lactic-co-glycolic acid
  • other polylactides and copolymers thereof having a Tg in the range of 40 - 65 °C can be lowered to below room temperature with the plasticizer.
  • the scaffold or composite matrix can be obtained by fusing together granular biomaterial such as polymeric granules and/or coated granules.
  • the scaffold or composite matrix of the biocompatible implant may be made of granules with indentations having micropores with average diameters of about larger than 0 to about 10 ⁇ m. By the fusion of the granules, the microporosity remains and/or macropores between the granules are formed having average diameters of about more than 10 ⁇ m to about 2000 ⁇ m, preferably about 100 ⁇ m to about 500 ⁇ m.
  • biocompatible scaffold or composite matrix which includes both coated and non-coated granules.
  • the coated and uncoated granules can be thoroughly mixed such that they fuse together and still have the needed stability.
  • the amount of coating materials, which must degrade may be further reduced.
  • the bone implant can also include a membrane on an outer surface, which prevents soft tissue in-growth and/or contamination and leaves space open for regeneration away from the outer surface.
  • the biocompatible membrane can be a degradable polymer film, polymer textile, polymer fleece or layer of interconnected fused polymer particles or a combination thereof and sealed to the implant, thus forming at least one layer of impermeability to soft tissue and epithelial cells.
  • the membrane is made of a synthetic, biocompatible and degradable polymer selected from the group including poly([alpha]-hydroxyesters), poly(ortho esters), poly(ether esters), polyanhydrides, poly(phosphazenes), poly(propylene fumarates), poly(ester amides), poly(ethylene fumarates), poly(amino acids), polysaccharides, polypeptides, poly(hydroxy butyrates), poly(hydroxy valerates), polyurethanes, poly(malic acid), polylactides, polyglycolides, polycaprolactones, poly(glycolide-co-trimethylene carbonates), polydioxanones, or copolymers, terpolymers thereof or blends of those polymers.
  • a synthetic, biocompatible and degradable polymer selected from the group including poly([alpha]-hydroxyesters), poly(ortho esters), poly(ether esters), polyanhydrides, poly(phosphazenes), poly(
  • Cell occlusive properties can also be achieved by fusing granules or coated granules together. If much force is applied, the coating or the linking polymer particles may fill up all intergranular porosity.
  • Granules used for this purpose preferably have a size smaller than about 500 ⁇ m and more preferably between about 1 ⁇ m to 200 ⁇ m.
  • formation of the implant composition includes (i) softening the polymers as to form an implant mass that is moldable (i.e., plastically deformable); and (ii) shaping the moldable implant mass into a desired shape (ex situ or in situ). In various embodiments of the present invention, these steps are performed in a different order and/or simultaneously.
  • the term "unshaped” means an implant mass that needs a substantial amount of molding to reach its final shape in a patient.
  • shaped means an implant that is sufficiently shaped such that it needs little or no molding to function as an implant in a patient.
  • an unshaped implant mass is formed and then softened. Coated granules are packed to form an unshaped implant mass. Implant mass has little or no plasticizer such that it is hard. Unshaped implant mass can be easily stored or shipped without affecting the implant's condition.
  • an initially hard and unshaped implant mass is conditioned using a plasticizer to yield a softened (or moldable) implant mass.
  • Moldable implant mass is then forced into a mold to form a shaped implant mass.
  • the mold can have any desired mold cavity (e.g. the shape of an extracted tooth root, a cylinder, or other regular or irregular shape).
  • a hardener is added to shaped implant mass in the mold, e.g. using a syringe.
  • the hardener is a liquid selected to extract or neutralize the plasticizer.
  • the hardener is a substance in which plasticizer is soluble.
  • the hardener draws the plasticizer out of the shaped implant mass thereby forming a hardened implant composition.
  • the hardener is water.
  • the implant is at least partially formed inside a bone defect.
  • polymer coated granules are placed in the bone defect prior to being softened with the plasticizer.
  • the plasticizer is injected into the void. The plasticizer softens at least a portion of the polymer, which allows the granules to adhere to one another to form an implant mass.

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  • Dermatology (AREA)
  • Transplantation (AREA)
  • Oral & Maxillofacial Surgery (AREA)
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  • Orthopedic Medicine & Surgery (AREA)
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  • Prostheses (AREA)
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EP16206784.7A 2016-12-23 2016-12-23 Bone graft substitute Withdrawn EP3338815A1 (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
EP16206784.7A EP3338815A1 (en) 2016-12-23 2016-12-23 Bone graft substitute
CN201780079095.2A CN110087699B (zh) 2016-12-23 2017-12-20 骨移植物替代物
PCT/EP2017/083829 WO2018115128A1 (en) 2016-12-23 2017-12-20 Bone graft substitute
EP17822278.2A EP3558404B1 (en) 2016-12-23 2017-12-20 Bone graft substitute
EP22203780.6A EP4144386B1 (en) 2016-12-23 2017-12-20 Bone graft substitute
US16/471,107 US20190321514A1 (en) 2016-12-23 2017-12-20 Bone graft substitute
JP2019534244A JP7197483B2 (ja) 2016-12-23 2017-12-20 骨移植片代用品
ES17822278T ES2954288T3 (es) 2016-12-23 2017-12-20 Sustituto de injerto óseo
US17/234,365 US20210236689A1 (en) 2016-12-23 2021-04-19 Bone graft substitute
US17/332,833 US20210283301A1 (en) 2016-12-23 2021-05-27 Bone graft substitute and methods for manufacturing same
US17/472,897 US20210402056A1 (en) 2016-12-23 2021-09-13 Bone graft substitute
JP2022062671A JP7483782B2 (ja) 2016-12-23 2022-04-04 骨移植片代用品

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EP17822278.2A Active EP3558404B1 (en) 2016-12-23 2017-12-20 Bone graft substitute
EP22203780.6A Active EP4144386B1 (en) 2016-12-23 2017-12-20 Bone graft substitute

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CN (1) CN110087699B (ja)
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US20210154015A1 (en) * 2019-11-27 2021-05-27 Igor Roshkovan Surgical Technique for alveolar ridge augmentation with maxillary sinus elevation (lateral approach) using a pre-portioned and ready pre-packaged graft composition in gelatin bag and method of producing it

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WO2018115128A1 (en) 2018-06-28
JP2020503109A (ja) 2020-01-30
EP4144386A1 (en) 2023-03-08
EP3558404B1 (en) 2023-06-07
JP7483782B2 (ja) 2024-05-15
EP3558404C0 (en) 2023-06-07
EP4144386B1 (en) 2024-04-03
US20210283301A1 (en) 2021-09-16
US20210236689A1 (en) 2021-08-05
EP4144386C0 (en) 2024-04-03
EP3558404A1 (en) 2019-10-30
ES2954288T3 (es) 2023-11-21
CN110087699B (zh) 2022-06-07
CN110087699A (zh) 2019-08-02
JP2022088628A (ja) 2022-06-14
US20190321514A1 (en) 2019-10-24
JP7197483B2 (ja) 2022-12-27

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